It may have all started Friday morning when someone claiming to be a 28-year-old “ordinary white” Australian posted a chilling, 74-page manifesto on the internet.

The screed suggested he was about to carry out a murderous attack on Muslims in New Zealand, a country he said was “target rich” for his immigrant death wish.

No one seems to have paid much attention.

But at about 1:40 p.m. local time that day, a white man resembling the manifesto’s author drove a light-coloured station wagon to a mosque in the centre of the city of Christchurch, hauled out a fearsome collection of firearms and calmly headed inside.

There he began a shooting rampage that would leave 49 worshippers dead at two mosques in the midst of Friday prayers, and dozens others injured.

This image from a self-shot video that was streamed on Facebook on March 15, 2019 by the man who was involved in two mosque shootings in Christchurch shows him holding a gun as he enters the Masjid al Noor mosque.AFP/Getty Images

Much of his cold-blooded assault was captured and live-streamed on Facebook by a camera apparently attached to the shooter’s helmet, one of the most horrific uses ever of the web technology.

More than an hour later, the suspected gunman was arrested in a dramatic takedown on a Christchurch sidewalk, police later charging a 28-year-old man with murder. By then, the world was in shock.

“It is clear that this is one of New Zealand’s darkest days,” said Prime Minister Jacinda Ardern. “Clearly, what has happened here is an extraordinary and unprecedented act of violence.”

As is often the case with mass shootings, this one began with a jarring contrast between the peacefulness of routine daily life and the shock of unprovoked violence.

Portions of the killer’s 17-minute video viewed by the National Post and accounts of the full recording by some other news media document the first gruesome moments. Exact timing is unknown, but police say emergency calls about gunshots at Al Noor mosque in central Christchurch started arriving at 1:40.

The man fished a long gun from the front seat of the car, then walked around and opened the hatchback, revealing a number of other weapons, all covered in white writing, much of it referencing typical “heroes” and symbols of white hate groups.

This photo of rifle ammunition appeared on a now-deleted Twitter account from a user whose name matched that of the Christchurch shootings suspect. The names mentioned include Quebec City mosque gunman Alexandre Bissonnette.Brenton Tarrant/Twitter

Among those commemorated on the decorated weapons were Alexandre Bissonnette, recently convicted for an attack on a Quebec City mosque in 2017 that killed six men. There was also the name of a Swedish man who murdered two migrant children, and Charles Martel, commander of Frankish forces that defeated an invading Arab army in the eighth century Battle of Tours.

Now armed, the video shows, the man enters a pleasant compound lined by shrubs and trees under a clear sky. A few men are standing in the entranceway.

“Hello, brother,” one calls out, a greeting that was soon to be immortalized on Twitter. The man uttering it was one of the first victims as the gunman opened fire on the group, dropping one long gun and shooting at worshippers who ran away with the second.

Inside the mosque, he fired at people crouching in fear, a strobe light attached to his automatic rifle flashing constantly. At first, faint screaming can be heard on the fuzzy soundtrack amidst the rattle of the gun, then there is near silence.

Entering a large prayer room, the gunman aimed at groups of people trying vainly to seek refuge in the corners. As one man attempted to rush past him, he swung around and shot him point blank.

Nour Tavis was in the front row of congregants in the mosque’s main prayer room when he and a friend detected what turned out to be gunfire, he told the New Zealand Herald.

“Then we heard screaming … everyone panicked,” the newspaper quoted Tavis as saying. “There was shooting and shooting and shooting … people were running and all of a sudden you saw them fall.”

Someone else smashed a window and jumped out, so Tavis followed, running for his life as more shooting reverberated from inside. He said he scaled a 1.5-metre fence and sought refuge in a neighbour’s home.

Back in the mosque, however, his friend’s wife was shot dead.

“She got the bullet, her husband got away,” Tavis recounted to the Herald. “She was gone, she was no more.”

After a couple of minutes, the video shows, the shooter leaves the mosque and returns to his car, picking up a different gun from the hatchback. Outside, he fires at bystanders, before walking back into the building, shooting at anyone still there and alive.

Members of the Bangladesh national cricket team, in town for a match against New Zealand, were moments from entering the mosque when they realized something terrible was happening inside.

Ambulance staff take a man from outside a mosque in central Christchurch, New Zealand, March 15, 2019.Mark Baker/AP

Hearing the shooting, they turned and fled through nearby Hagley Park, according to news reports.

Outside the mosque again, the gunman opens fire, appearing to hit one woman who was already injured and trying to crawl to help.

The man speeds away in the car, firing at one point through the windshield.

“There wasn’t even time to aim, there was so many targets,” he’s heard saying on the video, whether to himself or to his internet audience.

Authorities say 41 people died in those few minutes of random carnage at Al Noor, among them small children. At Linwood Mosque, about five kilometres away, seven people died. Another victim died at Christchurch Hospital.

David Meates, the chief executive of the Canterbury District Health Board, said 48 people, including young children, were treated for injuries. Two were in critical condition.

Witnesses at the Linwood Mosque told local media they started hearing gunshots at about 1:45, as several dozen men and women gathered to worship.

“Just around the entrance door there were elderly people sitting there praying and he just started shooting at them,” Syed Mazharuddin told the New Zealand Herald.

Locals lay flowers in tribute to those killed and injured near the Al Noor Mosque on March 16, 2019 in Christchurch, New Zealand.Fiona Goodall/Getty Images

At one point, said Mazharuddin, the gunman was rushed by a young man who worked at the mosque and managed to wrestle a weapon away from him.

The courageous mosque employee chased after the shooter, trying in vain to fire the gun he had taken from him but “there were people waiting for him in the car and he fled,” the witness said.

There were other heroics at the Linwood site, too. Another man had a gun and shot at the fleeing killer, say local media.

Witnesses complained that police and ambulances had taken an inordinate amount of time to arrive. But by just after 2:30 p.m., Christchurch police commissioner Mike Bush had urged everyone in the centre of the city to stay off the streets. He later warned Muslims to stay away from any mosque.

Shortly after 3 p.m., two improvised bombs found in a car were deactivated by a New Zealand military team.

And then, just before 3:30 p.m., according to news accounts, police arrested a suspect in dramatic, open-air fashion. A passing motorist’s video shows a vehicle pushed half off the road by a police cruiser, one of its wheels hovering above the road surface but still spinning.

A man was yanked from the car and wrestled to the ground, other officers pointing guns at him.

Two other people were also arrested, though their role in the mass murder, if any, was unclear.

Brenton Tarrant, a 28-year-old Australian, was charged with one count of murder and appeared briefly in court in handcuffs. The judge said while “there is one charge of murder brought at the moment, it is reasonable to assume that there will be others.”

Shortly after 4 p.m., the prime minister spoke to a horrified nation, strongly refuting the racist ideology behind the attacks.

“Many of those directly affected by this shooting may be migrants to New Zealand, they may even be refugees here,” Ardern said. “They have chosen to make New Zealand their home. It is their home. They are us. The person who has perpetrated this violence against us is not. They have no place in New Zealand.”